Method of making silicon monoxid



UNITE STAT srarnn'r onnion.

HENRY NOEL POTTER, OF NEW ROCHELLE, NEW YORK, ASSIGNOR TO GEO.WESTINGHOUSE,

OF PITTSBURG, PENNSYLVANIA.

METHOD OF MAKING SILICON MONOXID Specification of Letters Patent.

Patented May 5, 1908.

To all whom it may concern:

Be it known that I, HENRY NOEL POTTER, a citizen of the United States,and resident of New Rochelle, county of Westchester, State of New- York,have invented certain new and useful Improvements in Methods of MakingSilicon Monoxid, of which the following is a specification. I I havediscovered a novel method of making silicon monoxid which'differs'fromthat described in my original disclosure, constituting application -No.238,925, filed Dec. 30, 1904 The method described in my originalapplication may be said to consist in heating a mixture of silicondioxid and carbon to a critical temperature in a partially filledinclosing chamber.

My new method consists'in substituting for carbon or silicon as reducingagents appropriate quantities of light metals such as magnesiumor-aluminium. The process with magnesium may be represented by theexpression SiO Mg SiO MgO.

The reaction with aluminum may be expressed These reactions differ fromthe reaction with carbon in that the oxidation of the reducing agentgives a solid material instead of a gas, and this must be removed frommixture with the silicon monoxid whenever its presence is injurious. Inthecase of the magnesium reduction, the ma nesia produced may be removedby leachlng with hydrochloric acid. In the case of the aluminum, the AlO formed may be removed by digesting with hydrofluoric acid, whichattacks alumina more rapidly than it does silicon monoxid.

In practicing my invention, I mix appropriate' quantities of granular(preferably finely granular) materials together and heat them in anysuitable way, preferably with exclusion of air. At about a red heat, the

reactions begin and propagate themselves through the mass.

It might be thou ht that sodium or potas-' sium might be su stituted formagnesium or aluminum, but these powerfully alkaline metals give causticoxids which, while they are readily soluble in water, nevertheless ivesolutions which attack silicon monoxid. ilicon monoxid can, therefore,be produced in this way, but the process is attended with suchdifficulties as to be inferior in practicability to the processes basedon magnesium or aluminum, herein specified.

In practicing my invention, I find that it is advantageous to excludeatmospheric oxyen, whichmay be done by substituting an mert gas such ascarbon monoxid, or by op erating under such reduced pressure as toconstitute practically a vacuum, whereby. the amount of oxygen presentis reduced to a negligible quantity. Metallic calcium has also thenecessary properties to act as a reducing agent, but is at present tooexpensive to be available.

In practicing my invention, it is obviously not necessary to perform allthe reduction with a single reducing agent, as it is equally possible touse a mixture of aluminum and magnesium, or to combine the metallicreduction with. reductions involving carbon or silicon as reducing aents.

As a further mo mcation 'of an obvious nature, it is immaterial whetherthe mixture of two reducing agents (for example, aluminum and carbon,calcium and carbon, silicon and carbon, or siliconand magnesium) aresimply mechanical mixtures, or whether they are chemical compounds. Forexample, it is possible to use, as I have stated in a former aplication, silicon carbid instead of silicon and carbon. is possible touse calcium carbid instead of calcium and carbon, or magnesium silicidinstead of magnesium and SlllCOIl. Some of these compounds are nowobtainable in the market, as for example, calcium carbid, and otherssuch as magnesium silicid and the silicids of aluminum and calcium, canbe readily produced.

I claim-as my invention:

In a similar manner, it t 1. The method of producing silicon mon oxid,which consists in mixing silicon (lioxiil and a light metal and heatingthe mixture in an inert environment.

3. The method of producing silicon monoxid, which consists in mixingsilicon dioxid and a light metal and heating the mixture to about airedheat.

4. The process of producing silicon monoxid, which consists in reactingupon silica 13 with a metallic reducing agent, whereby the silica ispartially reduced and the metal is oxidized, and subse uentl removingthe oxy com ound of saiii meta Signe at New York, in the county of NewYork, and State of New York, this 7th day 15 of June A. D.. 1905.

' 'HENRY NOEL POTTER. Witnesses:

WM. H. CAIEL, GEORGE H. STOCKBRIDGE.

